This guide provides a comprehensive insight into understanding, monitoring and managing the capacity of GSM/UMTS networks. It is different from most sources of information on GSM and UMTS, as it provides a practical approach to engineers trying to measure and enhance the capacity of real-world networks. All of the major elements and interfaces of the RAN network are analyzed and guidelines are given to manage the capacity of the network. A brief overview of each technology is provided before capacity is discussed, but it is assumed that users of this guide will have a basic understanding of the technology they are trying to monitor. Basics of UMTS are emphasized more as compared to GSM, as in general, GSM is considered to be easier to measure, as the air interface is less complicated. It should be noted here that although this manual strives for completeness there will always be elements and areas of capacity which will be specific to different manufacturers. In such cases the reader should refer to the OEM vendor specific documentation for clarity and use this as a guide on what to measure.